1. Field of the Invention
This invention relates generally to a calcium fortified food product in the form of a ready-to-serve beverage, a frozen concentrate or a reconstitutable dry drink mix which provides between 10%-100% of the U.S. RDA of calcium per six ounce serving, which has a pH of not more than 4.5 and which has a Brix-acid ratio range of about 5:1 to 54:1.
2. The Prior Art
Calcium is the most abundant component of minerals present in the human body, comprising approximately two percent of total body weight. Calcium is continuously utilized by the body and is replenished by a variety of food sources. The several uses of calcium in the body include providing rigidity to the skeletal framework; serving as a catalyst for the conversion of prothrombin to thrombin, a compound necessary for blood clotting; increasing cell membrane permeability; activating a number of enzymes including lipase and adenosine triphosphatase; and acting as a component in the mechanisms of neural transmission and muscular contraction.
Given these representative vital usages of calcium by the body, it is recognized that a dietary calcium deficiency can have adverse effects on an individual's health which vary in degree depending upon age and sex. For example, calcium deficiency can interfere with muscular contraction and can also result in depletion of skeletal calcium, resulting in thin and brittle bones.
This latter malady is known as osteoporosis. Osteoporosis (porous bones) is a deficiency disease, a condition in which there are varying degrees in the loss of bone density or actual bone loss. Adult bone loss is considered one of the most debilitating health problems for elderly people. Although bone loss occurs in both men and women as they age, women suffer more often and with more devastating effects. This is due in part to the fact that women, in general, have smaller skeletal structures than men and also undergo accelerated bone loss at menopause due to estrogen loss. This crippling disease affects approximately one out of four women over the age of 60. The bones become more susceptible to breaks; subsequent fractures have a lower chance of healing which often leads to fatal complications.
Several studies conducted in recent years have shown that increased dietary intake of calcium may be effective in minimizing bone loss in elderly or post menopausal women. It is thought that increased consumption of calcium in early years builds reserves that enable a greater tolerance of a negative calcium balance in later years.
Some researchers suggest that raising calcium intake to 1200 mg-1400 mg per day would help restore positive calcium balance in most women between the ages of 35 and 50. Other data indicate even higher levels up to 1900 mg per day may be effective for treating post menopausal women. Calcium intakes of up to 2500 mg per day are considered safe in most healthy individuals. These high levels, however, may not be beneficial and may result in hypercalcemia or kidney stones.
Foods fortified with calcium and calcium supplements are being used more often by the U.S. consumer and are generally considered by some researchers to offer the same net effect as calcium naturally found in food. The most effective order of relative bioavailability or intestinal absorption of various calcium salts is still controversial. There is no consensus among medical authorities as to the effectiveness of one calcium salt over another.
Nevertheless, there are several known factors which affect the absorption of calcium by the human body. In healthy adults approximately 30 percent of calcium contained in their diets is absorbed. The absorption of calcium from various foods may range from 10% to 40%. Generally, at very high intakes the efficiency of the absorption process decreases. The body's need is probably the most significant factor in controlling this absorption process through feedback mechanisms. Children and pregnant/lactating women absorb an average of 40% of the calcium in their diets.
Vitamin D (active) is the major regulator of intestinal absorption of calcium. Calcium intakes can therefore be more efficiently utilized when there is an abundant supply of vitamin D. Sunlight (ultraviolet light) is considered an important factor in the conversion of dietary precursors to vitamin D, especially for young people. The dietary sources of active vitamin D may become essential in elderly adults who are less likely to be exposed to sunlight.
Acid solutions enhance the solubility of calcium salts. Much of the digestion of foods takes place in the duodenum where the pH of the gastric juices is low. Since calcium salts are more soluble in an acid pH, much of the absorption of calcium takes place in this segment of the gastrointestinal tract. Tricalcium phosphate, calcium lactate, calcium carbonate and many other calcium compounds have all been used as calcium sources in various calcium fortified products. In "Nutrition and Metabolic Bone Disease With A Special Emphasis On The Role Of Calcium", Pak, C. Y. C., Medical Grant Rounds, Southwestern Medical School, Mar. 6, 1986, it is disclosed that calcium citrate is the preferred salt for calcium fortification in certain juices. Several commercially available products such as antacids disclose the use of calcium carbonate as a dietary calcium supplement.
The recommended daily allowance (RDA) of a mineral is the gender-specific recommendation considered by scientific experts to be adequate to meet the need for that nutrient for virtually all healthy people in the population. The current RDA of calcium is 360 to 800 mg for children depending on age. 12. The RDA for teenagers from 11-15 years is 1200 mg and is 800 mg for adults. Pregnancy and lactation increase the recommended amount by about 400 mg per day. The U.S. Recommended Daily Allowances (U.S. RDA) are derived from the 1968 RDA and are standards specified by the Food and Drug Administration to simplify nutritional labelling.
Dairy products are recognized as a rich source of dietary calcium, in some instances accounting for as much as 75% of an individual's dietary intake of calcium. Increased ingestion of dairy products, however, has several drawbacks which preclude their broad recommendation as a solution for dietary calcium deficiency. These drawbacks include lactose intolerance by some individuals; the high levels of cholesterol and cholesterol producing ingredients in dairy products; the high caloric yields of dairy products; and flavor off-tastes often experienced by elderly individuals.
Various beverages have been disclosed which contain a calcium compound in amounts which vary depending upon the purpose of the calcium additive.
U.S. Pat. No. 3,227,562 discloses a citrus fruit juice concentrate having a low Brix to acid ratio. As disclosed in the '562 patent, which is hereby incorporated by reference, the Brix unit is a commonly used unit of measurement which expresses the concentration of dissolved solids in an aqueous solution. The acid unit is the citric acid concentration in the citrus juice. The Brix to acid ratio is the accepted measurement of the sweetness to tartness ratio used in the fruit juice industry. A Brix-Acid ratio is obtained by dividing the Brix value by the acid value for a given product which yields a ratio compared with unity which forms a comparative scale for acceptability for particular juice concentrates. Brix-acid ratios of concentrated citrus fruit juice, high grade fresh--frozen orange juice concentrate will usually have a range of Brix-acid ratios of about 12.5:1 to about 20:1 whereas a range for grapefruit juice would be about 7:1 to about 11:1. Brix-acid ratios for commercially available citrus fruit juice-containing drinks generally range from 17:1 to 54:1. High quality commercially available orange juice products usually have a Brix-acid ratio range of 16:1 or higher.
The '562 patent attributes the characteristic aftertaste of its concentrate to a combination of salts comprising sodium chloride, magnesium chloride, calcium chloride and sodium silicate with a citrus concentrate comprised of orange, lemon grapefruit and lime. The level of calcium chloride contained in the concentrate of the '562 patent is in the range of 3 mg per 6 ounce serving with the bulk of the salt used to impart the pleasant aftertaste consisting of sodium chloride. This level provides an extremely low amount of calcium and will not deliver the requisite dietary amounts of calcium thought to be effective in the prevention of osteoporosis and the like.
U.S. Pat. No. 3,657,424 discloses a citrus juice energy supplement which replenishes salts whose natural level in the body has been depleted, e.g., through exercise. This reference discloses the addition of a combination of salts, including sodium chloride, potassium chloride and calcium chloride, in amounts that do not exceed 0.2% percent by weight of the beverage. The calcium chloride present in the fruit juice disclosed in the '424 patent ranges from 0-0.04% by weight or approximately 30 mg of calcium per 6 ounce serving of fortified product.
In U.S. Pat. No. 4,551,342 a beverage containing specific cation-edible acid mixtures for improved flavor retention is disclosed in which the flavor of carbonated sugar-or aspartame-sweetened beverages is improved by using a specific ratio of acids to cations. The acids used are citric, malic, succinic and phosphoric and the cations used are calcium, magnesium and potassium. The '342 patent discloses the use of calcium carbonate and calcium hydrogen malate as sources of calcium. These sources of calcium are added in amounts which range from 0.04-0.12% by weight of the final beverage, which corresponds to about 29-83 mg of calcium per six ounce serving. This level also provides only a low dietary amount of calcium.
Attempts to increase the calcium levels in these prior art beverages produce an unpleasant gritty drink. Moreover, at calcium levels in the drink that are needed to promote significant absorption levels in the gut, the calcium salts begin to exhibit precipitation.
Consequently, it is an object of the present invention to develop a calcium fortified food product in ready-to-serve and readily ingestible form which can provide a substantial amount and a readily absorbable form of the recommended daily allowance of calcium. In particular, it is an object to develop a food product, e.g., a beverage, which can provide approximately 100 mg-1,000 mg of calcium per six ounce serving and which has a Brix-acid ratio of about 5:1 to about 54:1, preferably about 7:1 to about 20:1 for citrus products. A further object is the development of a food product which can be handled as a concentrate yet is fairly soluble in water and, when reconstituted, has a pH which does not exceed the upper levels for high acid food, e.g. about 4.5.